1. Field of the Invention
The present invention pertains to the construction of a manually operated trigger sprayer in which the conventional metal coil spring and separate piston rod are replaced with an integral plastic spring and pump piston rod that are connected by a breakable connection, whereby the spring and piston rod can be assembled to the trigger sprayer as one piece and are subsequently broken into two separate pieces in response to their assembly to the trigger sprayer, or subsequent manual operation of the trigger sprayer.
2. Description of the Related Art
Handheld and hand pumped liquid dispensers commonly known as trigger sprayers are used to dispense many household products and commercial cleaners. Trigger sprayers have been designed to selectively dispense the liquids in a spray, stream, or foaming discharge. The trigger sprayer is typically connected to a plastic bottle that contains the liquid dispensed by the sprayer.
A typical trigger sprayer includes a sprayer housing that is connected to the neck of the bottle by either a screw thread connection or a bayonet-type connection. The sprayer housing is formed with a pump chamber, a liquid supply passage that communicates the pump chamber with a liquid inlet opening of the sprayer housing, and a liquid discharge passage that communicates the pump chamber with a liquid outlet opening of the sprayer housing. A dip tube is connected to the sprayer housing liquid inlet opening to communicate the pump chamber with the liquid contents of the bottle connected to the trigger sprayer.
A nozzle assembly is connected to the sprayer housing at the liquid outlet opening. Some nozzle assemblies include a nozzle cap that is rotatable relative to the sprayer housing between an “off” position where liquid discharge from the trigger sprayer is prevented, and one or more “on” positions where liquid discharge from the trigger sprayer is permitted. In addition, known nozzle assemblies can affect the liquid discharged by the trigger sprayer to discharge the liquid in a spray pattern, in a stream pattern, or as a foam.
A pump piston is mounted in the sprayer housing pump chamber for reciprocating movement between charge and discharge positions of the piston relative to the pump chamber. When the pump piston is moved to its charge position, the piston is retracted out of the pump chamber. This creates a vacuum in the pump chamber that draws liquid from the bottle, through the dip tube and into the pump chamber. When the pump piston is moved to its discharge position, the piston is moved into the pump chamber. This pumps the liquid from the pump chamber, through the liquid discharge passage of the sprayer housing and out of the trigger sprayer through the nozzle assembly.
A metal coil spring is positioned in the pump chamber and engages with the pump piston. The coil spring biases the pump piston toward the discharge position of the piston. Some known trigger sprayers have plastic springs in their pump chambers or mounted on the exterior of the sprayer housing.
A trigger is mounted on the sprayer housing for movement of the trigger relative to the trigger sprayer. The trigger is operatively connected to the pump piston to cause the reciprocating movement of the pump piston in the pump chamber in response to movement of the trigger. A user's hand squeezes the trigger toward the sprayer housing to move the trigger and move the pump piston toward the discharge position of the piston in the pump chamber. The spring pushes the piston back to the charge position of the piston relative to the pump chamber when the user's squeezing force on the trigger is released.
Inlet and outlet check valves are assembled into the respective liquid supply passage and liquid discharge passage of the trigger sprayer. The check valves control the flow of liquid from the bottle interior volume through the liquid supply passage and into the pump chamber, and then from the pump chamber and through the liquid discharge passage to the nozzle assembly of the trigger sprayer.
The typical construction of the trigger sprayer discussed above has several separate component parts. The manufacturing of each of these individual component parts contributes to the overall cost of manufacturing the trigger sprayer. In the typical trigger sprayer construction where most of the component parts are molded of a plastic material, there is a cost associated with the molding of each of the individual parts and a cost associated with assembling each of the individual parts into the trigger sprayer. Because trigger sprayers are manufactured and sold in very large numbers, even a slight reduction in the manufacturing costs of a trigger sprayer, for example by reducing the number of component parts of the trigger sprayer or reducing the assembly steps required in manufacturing the trigger sprayer could result in a significant overall reduction in the cost of manufacturing large numbers of trigger sprayers.